title: Preparation of ordered mesoporous alumina-doped titania films with high thermal stability and their application to high-speed passive-matrix electrochromic displays.
abstract: Ordered mesoporous alumina-doped titania thin films with anatase crystalline structure were prepared by using triblock copolymer Pluronic P123 as structure-directing agent. Uniform Al doping was realized by using aluminum isopropoxide as a dopant source which can be hydrolyzed together with titanium tetraisopropoxide. Aluminum doping into the titania framework can prevent rapid crystallization to the anatase phase, thereby drastically increasing thermal stability. With increasing Al content, the crystallization temperatures tend to increase gradually. Even when the Al content doped into the framework was increased to 15 mol %, a well-ordered mesoporous structure was obtained, and the mesostructural ordering was still maintained after calcination at 550 °C. During the calcination process, large uniaxial shrinkage occurred along the direction perpendicular to the substrate with retention of the horizontal mesoscale periodicity, whereby vertically oriented nanopillars were formed in the film. The resulting vertical porosity was successfully exploited to fabricate a high-speed and high-quality passive-matrix electrochromic display by using a leuco dye. The vertical nanospace in the films can effectively prevent drifting of the leuco dye.
authors.affiliation: World Premier International Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Xiangfen
authors.initials: X
authors.lastname: Jiang
authors.forename: Bishnu Prasad
authors.initials: BP
authors.lastname: Bastakoti
authors.forename: Wu
authors.initials: W
authors.lastname: Weng
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higuchi
authors.forename: Hamid
authors.initials: H
authors.lastname: Oveisi
authors.forename: Norihiro
authors.initials: N
authors.lastname: Suzuki
authors.forename: Wei-Jung
authors.initials: WJ
authors.lastname: Chen
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Huang
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamauchi
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry; D003460:Crystallization; D055664:Electrochemical Techniques; D004566:Electrodes; D006358:Hot Temperature; D011060:Poloxalene / Q000737:chemistry; D016062:Porosity; D053838:Scattering, Small Angle; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004396:Coloring Agents; C009495:titanium dioxide; C464484:pluronic block copolymer P123; D011060:Poloxalene; D014025:Titanium; D000537:Aluminum Oxide
keywords: display technology; doping; electrochomism; mesoporous materials; thin films